Introduction to Animals

All living things used to be classified into 5 kingdoms before we reorganized it into the 3 domains and 6 supergroups we’ve learned about.

Characteristics of all Animals

Animal Characteristics DEFINING CHARACTERISTCS OF ANIMALS 1. Heterotrophs: ingest their food 2. Multicellular: 3. Eukaryotic: animal cells with a nucleus and organelles (large diversity of cell specialization) 4. No cell walls TWO MAIN DIVISIONS: Invertebrate: all other phyla without internal skeletons Vertebrate: Phylum Chordata – internal skeleton

Eucaryotic (The cell has a nucleus)

Multicellular (allows cell specialization) Specialized cells are more efficient than non-specialized cells

Heterotropic (They obtain food by eating other organisms (herbivores, carnivores or omnivores)).

Can move (are motile) at some point in their life

Respond to stimuli (nerves)

Respiration – moves oxygen into the organism and removes CO2

Most animals reproduce sexually but some can reproduce asexually

Cell Specialization Animals contain many specialized cells each has a shape, physical structure, and chemical composition that make it suited for it’s particular function called “division of labor” specialized cells perform tasks much more efficiently

Symmetry None – Porifera Radial – Cnidaria Bilateral – All others Pentamerous Radial Symmetry – Echinoderm Adults only Earland

Concentration of nerves and sense organs at the front end or head of the organism.

Body cavities – Acoelom (no body cavity)

False body cavity - Pseudocoelomate – partial fluid filled body cavity (coelom) -Partly lines with internal tissue (mesoderm) - Internal organs are loosely held in place

True body cavity - coelom Coelom – fluid filled body cavity, completely lined with internal tissue (mesoderm). Has suspended internal organs

Earland

Tissue Layers Endoderm - digestion and respiration structures Mesoderm - muscles, bones, blood, and reproductive organs Ectoderm - skin, brain, and nervous system

Animal Systems In order to survive, animals must be able to perform a number of essential functions Feeding Respiration Internal Transport Excretion Response Movement Reproduction

The 7 Essentials Feeding – heterotroph, autotroph, etc. Respiration – skin or full system Internal Transport – closed or open circulation Excretion – waste removal Response – nerve cells – brain- specialized organs Movement – exo or endoskeleton, muscles Reproduction – sexual or asexual